A machine tool discharging cutting liquid as a mist from a tip of a spindle is known as a machine tool reducing usage of cutting liquid to protect the environment. This machine tool discharges the cutting liquid from a tip of a tool as a mist while cutting work. However, when the spouting of the cutting liquid is late, burn-in or damage is caused. Therefore, a response to a mist spouting has been studied.
For example, a machine tool disclosed in Japanese Patent No. 3087119 prevents leaking by sucking a fixed amount of cutting liquid in a cutting liquid supply line when a pump is stopped from supplying the cutting liquid. In this machine tool, late response is prevented by returning the cutting liquid sucked at the start of supply to the cutting liquid supply line again.
Japanese Unexamined Patent Application Publication No. 6-201094 discloses a machine tool not discharging a mist but detecting with a monitoring device the pressure provided to piping in which lubricant is fed from a pump. In this machine tool, a bearing is prevented from burning by displaying a piping leak when the pressure is lower than a minimum alarm pressure.